/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | foam-extend: Open Source CFD
   \\    /   O peration     | Version:     4.1
    \\  /    A nd           | Web:         http://www.foam-extend.org
     \\/     M anipulation  | For copyright notice see file Copyright
-------------------------------------------------------------------------------
License
	This file is part of foam-extend.

	foam-extend is free software: you can redistribute it and/or modify it
	under the terms of the GNU General Public License as published by the
	Free Software Foundation, either version 3 of the License, or (at your
	option) any later version.

	foam-extend is distributed in the hope that it will be useful, but
	WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
	General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with foam-extend.  If not, see <http://www.gnu.org/licenses/>.

\*---------------------------------------------------------------------------*/

#include "GAMGSolver.H"
#include "vector2D.H"

// * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //

Foam::scalar Foam::GAMGSolver::scalingFactor
(
	scalarField& x,
	const scalarField& b,
	const scalarField& Ax,
	const scalarField& D
) const
{
	scalar scalingFactorNum = 0.0;
	scalar scalingFactorDenom = 0.0;

	forAll(x, i)
	{
		scalingFactorNum += b[i]*x[i];
		scalingFactorDenom += Ax[i]*x[i];

		// While the matrix-multiply done for the scaling it is
		// possible to perform a point-Jacobi smoothing operation cheaply
		x[i] += (b[i] - Ax[i])/D[i];
	}

	vector2D scalingVector(scalingFactorNum, scalingFactorDenom);
	reduce(scalingVector, sumOp<vector2D>());
	return scalingVector.x()/stabilise(scalingVector.y(), VSMALL);
}


Foam::scalar Foam::GAMGSolver::scalingFactor
(
	scalarField& Ax,
	const lduMatrix& A,
	scalarField& x,
	const FieldField<Field, scalar>& coupleLevelBouCoeffs,
	const lduInterfaceFieldPtrsList& interfaceLevel,
	const scalarField& b,
	const direction cmpt
) const
{
	A.Amul
	(
		Ax,
		x,
		coupleLevelBouCoeffs,
		interfaceLevel,
		cmpt
	);

	return scalingFactor
	(
		x,
		b,
		Ax,
		A.diag()
	);
}


// ************************************************************************* //
